Monday, 28 December 2015
Sunday, 27 December 2015
Saturday, 26 December 2015
Friday, 18 December 2015
What is a GMO?
o A genetically modified organism (GMO) is an organism (plant, animal, bacteria or virus) whose genetic makeup has been modified for a particular purpose.
o The organism does not occur naturally in this modified state.
o For example, a plant can be modified to carry an additional gene found in another living thing (such as a bacteria) to protect itself against insect pests.
o Genes carry the information or the “recipe”, in the sequences and structures of DNA, which gives the organism its specific characteristics.
o Genes can be added, removed or changed, using modern biotechnology methods.
o Because Genes are common to life on earth, genes can be transferred from one organism to another and even between non-related species.
o This manipulation can produce a product with new characteristics which may have advantages.
How are GMOs useful to us?
- GM (genetically modified) plants are already being cultivated as crops and consumed by humans and animals.
- Using genetic engineering, new improved varieties of crops can be produced more quickly than with conventional breeding methods.
- Crops can be modified to have valuable characteristics such as tolerance to drought and herbicides, resistance to disease and insects, as well as improved nutritional content.
- · Insulin as a treatment for diabetes was the first commercial healthcare product produced by GMOs.
- · Bacteria were genetically modified to have a copy of the human insulin gene, and the protein is synthesized by the bacteria.
- · GMOs can produce other medicines such asgrowth hormone.
- · GMOs are used in current vaccines such as Hepatitis B (produced by yeast), and new vaccines are being developed using GMO technology.
- · In the future, plants may even be engineered to contain the vaccines so that we may be able to eat our vaccinations rather go for an injection.
- · In the future, GMOs may be used for gene therapy to correct certain genetic conditions.
- · GM cotton has been created to be resistant to insect attack to improve the yield of the crop.
Adaptive immunity is capable of recognizing and selectively eliminating specific foreign microorganisms and molecules
(i.e., foreign antigens).
Unlike innate immune responses, adaptive immune responses are not the same in all members
of a species but are reactions to specific antigenic challenges.
Adaptive immunity displays four characteristic attributes:
- · Antigenic specificity
- · Diversity
- · Immunologic memory
- · Self/nonself recognition
The antigenic specificity of the immune system permits it to distinguish subtle differences among antigens.
Antibodiescan distinguish between two protein molecules that differ in only a single amino acid.
The immune system is capable ofgenerating tremendous diversity in its recognition molecules,
allowing it to recognize billions of unique structures on foreign antigens.
Once the immune system has recognized and responded to an antigen, it exhibits immunologic memory;
that is, a second encounter with the same antigen induces a heightened state of immune reactivity.
Because of this attribute, the immune system can confer life-long immunity to many infectious agents after an initial encounter.
Finally, the immune system normally responds only to foreign antigens, indicating that it is capable of self/nonself recognition.
The ability of the immune system to distinguish self from nonself and respond only to nonself molecules is essential, for, as described below, the outcome of an inappropriate response toself molecules can be fatal.
Adaptive immunity is not independent of innate immunity.
The phagocytic cells crucial to nonspecific immune responses are intimately involved in activating the specific immune response.Conversely, various soluble factors produced by a specific immune response have been shown to augment the activity of these phagocytic cells.
As an inflammatory response develops, for example, soluble mediators are produced
that attract cells of the immune system.
The immuneresponse will, in turn, serve to regulate the intensity of the inflammatory
Through the carefully regulated interplay of adaptive and innate immunity, the two systems work
together to eliminate a foreign invader.
The Adaptive Immune System Requires Cooperation Between Lymphocytes and Antigen-Presenting Cells
Wednesday, 16 December 2015
Waste water and sewage treatmentItruduction;
While many ancient civilisations had an appreciation of the need to protect the quality of water to be used for human consumption, it was not until 1855 that it was demonstrated that cholera was transmitted by water contaminated by faeces.
A similar route for typhoid fever was shortly to
be demonstrated. By the end of the nineteenth century, the microbial ecology of many human diseases had been shown to have an anal–oral route of transmission, which finally confirmed the health hazards associated with water contaminated with faeces. The introduction of sewage systems in developed societies during the nineteenth century allowed, for the first time, the possibility of treatment of municipal and industrial wastes before
discharging into natural water systems.
Growth in human populations has generally been matched by a concomitant formation of a wider range of waste products, many of which cause serious environmental pollution if they are allowed to accumulate in the ecosystem.
In rural communities recycling of human, animal andvegetable wastes has been practised for centuries, providing in many cases valuable fertilisers or fuel. However, it was also a source of disease to humans and animals by residual pathogenicity of enteric (intestinal) bacteria.
In urban communities, where most of the deleterious wastes accumulate, efficient waste collection and specific treatment processes have been developed since it is impractical to discharge high volumes of waste into natural land and waters. The introduction of these practices in the last
century was one of the main reasons for the spectacular improvement in health and well-being in the developed countries.
Mainly by empirical means a variety of biological treatment systems have been developed, ranging from cesspits, septic tanks and sewage farms to gravel beds, percolating filters and activated sludge processes coupled with anaerobic digestion. The primary aims of all of these systems or bioreactors is to alleviate health hazards and to reduce the amount of biologically oxidisable organic compounds, producing a final effluent or outflow that can be discharged into the natural environment without any adverse
Such bioreactor assemblies rely on the metabolic versatility of mixed microbial populations (microbial ecology) for their efficiency.
The systems in which they perform their biological functions can be likened to other industrial bioreactors (e.g. antibiotic production); large-scale plants, for example municipal forced aeration tanks can be extremely complex,
requiring the skills of the engineer and the microbiologist for successful operation.
The fundamental feature of these bioreactors is that they
contain a range of microorganisms with the overall metabolic capacity to degrade most organic compounds entering the system.
The development of these systems was an early example of biotechnology.
Indeed, in volumetric terms biological treatment of domestic waste waters and sewerage in the industrialised nations is by far the largestbiotechnological industry, and the least recognised by lay people.
Controlled use of microorganisms has led to the virtual elimination of such waterborne diseases as typhoid, cholera and dysentery in these communities.
Yet, if water and sewage treatments are seriously interrupted, major epidemics may quickly develop as witnessed in 1968 in Zermatt, Switzerland, where typhoid developed following the breakdown of the water treatment plant.
Thus, biotechnology not only generates a whole new range of useful products, it also plays an indispensable part, through water and sewage treatment processes, in the reduction of infectious diseases of humans and animals.
The biological disposal of organic wastes is achieved in many ways throughout the world widely used practice for sewage treatment is shown in Fig.
three stages of primary and secondary processing followed by microbial digestion.
An optional tertiary stage involving chemical precipitation may
The primary activity is to remove coarse particles and solubles
leaving the dissolved organic materials to be degraded or oxidised
by microorganisms in a highly aerated, open bioreactor.
This secondary process requires considerable energy input to drive the mechanical aerators that actively mix the whole system, ensuring regular contact of the microorganisms with the substrates and air. The microorganisms multiply and form a biomass or sludge, which can either be removed and dumped, or
passed to an anaerobic digester (bioreactor) that will reduce the volume of solids, the odour and the number of pathogenic microorganisms.
A further useful feature is the generation of methane or biogas, which can be used as a fuel.
However, the value of biogas is marginal because of its content of carbon dioxide and hydrogen sulphide.
Another important means of degrading dilute organic liquid wastes is the percolating or trickling filter bioreactor. In this system the liquid flows over a series of surfaces, which may be stones, gravel, plastic sheets, on which attached microbes remove organic matter for essential growth.
Excessive microbial growth can be a problem, creating blockages and loss of biological activity. Such techniques are widely used in water purification systems.
Abundant availability of water is vital for modern urban and industrial development. Water makes up more than 70% of the human body and about two litres a day is usually sufficient to keep an adult healthy.
Water acts as a transport medium for essential nutrients within the body, helps to remove toxins and waste materials, stabilises body temperature and performs a crucial part in the structure and function of the circulatory system. In essence, water is the elixir of life.
In the natural world the ecosystem regenerates and recycles water.
Increasingly, human intrusion into nature by industrialisation, extensive farming practices, deforestation, etc., has severely unbalanced this process. It is now accepted that two-thirds of the world’s nations are water-stressed – using clean water
faster than it is replenished in aquivers or rivers.
Biotechnology will play an important role for reclamation and purification of waste waters for re-use.
Water must be recycled in the sustainable use of resources. The most important threat mankind faces in the coming decades is not global warming or energy deficiency but an increasing shortage of high-quality water.
What are the future areas of importance? Microbiological effluent treatment will be a major field of biotechnological interest in the future.
Integrated systems will be developed for treating complex wastes.
The role of the biocatalyst or microbe will be constantly reassessed.
Biotechnologists are now designing increasingly specific and efficient bioreactors to contain selected consortia of microorganisms best adapted to a range of different waste streams.
In countries with high annual hours of sunlight there has been considerable development of combined algal/bacterial systems for waste and water treatments. Such processes can lead to the formation of relatively pure water and algal/bacterial biomass, which may be used for animal feeding, biogas formation or, perhaps more ambitiously, for bulk organic chemical formation.
A comparison of several widely used treatment processes for liquid wastes is shown in Table 7.1, while Table 7.2 defines the various operating components.
Water is now being recognised as an increasingly expensive component of many industrial processes. Industries worldwide use vast quantities of quality water in their manufacturing procedures, e.g. steel, textiles, food, etc. For example, for each tonne of steel produced approximately 280 tonnes of water will be used.
In the past many of these industries simply
discharged the waste water into water courses often resulting in extensive down-river or estuarine pollution. Stringent anti-pollution laws together with greatly increased water charges have prompted such companies to develop new waste-water treatment systems that function in a closed-loop manner.
Almost two-thirds of water consumption worldwide is utilised for agricultural irrigation.
In many cases where water is in short supply raw
domestic sewage is used, which invariably leads to crop contamination
ADVANTAGES OF WASTE WATER TREATMENT
- High BOD removal efficiency.
- Low operating costs.
- Low operator skills required.
- Sensitive to cold weather.
- Activated sludge High BOD removal efficiency.
- Moderate ground requirements.
- Trickling filters Low operator costs.
- Moderate space requirements. Resistant to sudden high inputs.
There is little doubt that modern biology is the most diversified of all the
natural sciences, exhibiting a bewildering array of subdisciplines: microbiology,
plant and animal anatomy, biochemistry, immunology, cell biology,
molecular biology, plant and animal physiology, morphogenesis, systematics,
ecology, genetics and many others.
The increasing diversity of modern
biology has been derived primarily from the largely post-war introduction
into biology of other scientific disciplines such as physics, chemistry and
mathematics, which have made possible the description of life processes at
the cellular and molecular level. In the last two decades well over 20 Nobel
prizes have been awarded for discoveries in these fields of study.
This newly acquired biological knowledge has already made vastly
important contributions to the health and welfare of mankind. Yet few
people fully recognise that the life sciences affect over 30% of global economic
turnover by way of healthcare, food and energy, agriculture and
forestry, and that this economic impact will grow as biotechnology provides
new ways of influencing raw material processing.
Biotechnology will increasingly affect the efficiency of all fields involving the life sciences, and it is now realistically accepted that by the early twenty-first century it will
be contributing many trillions of pounds to world markets.
In the following chapters, biotechnology will be shown to cover a multitude
of different applications ranging from the very simple and traditional,
such as the production of beers, wines and cheeses, to highly complex
molecular processes, such as the use of recombinant DNA technologies to
yield new drugs or to introduce new traits into commercial crops and animals.
The association of old traditional industries such as brewing with
modern genetic engineering is gaining in momentum, and it is not for
nothing that industrial giants such as Guinness, Carlsberg and Bass are
heavily involved in biotechnology research. Biotechnology is developing at
a phenomenal pace, and will increasingly be seen as a necessary part of the
advance of modern life and not simply a way to make money!
While biotechnology has been defined in many forms (Table 1.1), in
essence it implies the use of microbial, animal or plant cells or enzymes to
synthesise, break down or transform materials.
The European Federation of Biotechnology (EFB) considers biotechnology
as ‘the integration of natural sciences and organisms, cells, parts
thereof, and molecular analogues for products and services’.
Sunday, 13 December 2015
- Cancer is a tumour.
- It is an abnormal growth or enlargement of tissue.
- It has no co-ordination with normal tissue.
- It is an independent,autonomus,uncontrolled growth of a tissue containing a mass of abnormal cells.
- A tumour serves no useful purpose but is harmful as it grows at the expense of the host like a parasite.
- Cancer now cause the second largest no.of deaths in most countries.
- There is no cure for cancer.
Types of tumour:
- The tumour is two types, namely benign tumour and malignant tumour.
- The benign tumour remains fixed in the place of origin.
- It will not spread from one place to other.
- It can be cured by surgically removing the tissue.
- It spread from one place to another through circulation and invasion.
- The spreading of tumour from one place to another is called metastasis.
Characteristics of Cancer:
- A tumour arises from an existing tissue or cells of the body.
- The growth of tumour is autonomous i.e. it follows
- its own laws of growth, it is not regulated by those governing the tissue from
- which or in which it grows.
- The tumour cells are undifferntiated and anaplastic in nature.
- Anaplasia refers to the reversion of differentiated cells into
- undifferentiated or embryonic cells.
- They have a greater potentially for growth and multiplication.
- They carry out none of the function of normal adult cells.
- They have large and irregular nuclei.
- They lose their contact inhibition.